List of top Linear Algebra Questions asked in GATE MA

Consider the problem of maximizing \[ z = \begin{pmatrix} x_1 & x_2 & x_3 \end{pmatrix} \begin{pmatrix} 2 & 0 & 0 \\ 0 & 2 & 1 \\ 0 & 1 & 2 \end{pmatrix} \begin{pmatrix} x_1 \\ x_2 \\ x_3 \end{pmatrix} \] subject to \[ \begin{pmatrix} x_1 & x_2 & x_3 \end{pmatrix} \begin{pmatrix} x_1 \\ x_2 \\ x_3 \end{pmatrix} = 1, \] where \( \begin{pmatrix} x_1 \\ x_2 \\ x_3 \end{pmatrix} \in \mathbb{R}^3 \).

Then the maximum value of \( z \) is ______. (Answer in integer)

Let \( P_3(\mathbb{R}) \) be the vector space of all polynomials of degree at most three with real coefficients under usual polynomial addition and scalar multiplication. Let \( T: P_3(\mathbb{R}) \to \mathbb{R}^2 \) be the linear transformation defined as \[ T(p) = \left(p(1), p'(1)\right) \] for all \( p \in P_3(\mathbb{R}) \), where \( p' \) is the derivative of \( p \).

Then the nullity of \( T \) is equal to ______. (Answer in integer)

Let \[ J = \begin{pmatrix} 2 & 1 & 0 & 0 & 0 & 0 \\ 0 & 2 & 0 & 0 & 0 & 0 \\ 0 & 0 & 2 & 1 & 0 & 0 \\ 0 & 0 & 0 & 2 & 0 & 0 \\ 0 & 0 & 0 & 0 & 3 & 1 \\ 0 & 0 & 0 & 0 & 0 & 3 \end{pmatrix}. \] Then the geometric multiplicity of the eigenvalue \(2\) of \(J\) is equal to ________. (Answer in integer)

Let \(P\) and \(Q\) be \(3 \times 3\) nonzero real matrices. Assume that there exists a \(3 \times 3\) real nonsingular matrix \(S\) such that \(S^{-1}PS\) and \(S^{-1}QS\) are both upper triangular. Which of the following statements is/are TRUE?

Let \(P = \begin{pmatrix} 1 & 0 & 0 \\ 0 & 9 & 0 \\ 0 & 0 & 16 \end{pmatrix}\). Define an inner product on \(\mathbb{R}^3\) with respect to \(P\) as \[ \langle x,y\rangle_P = x^{\top}Py, \quad \text{for all } x,y \in \mathbb{R}^3. \] Consider the subspace \(V = \text{span}\left\{\begin{pmatrix}1\\0\\0\end{pmatrix}, \begin{pmatrix}1\\1\\1\end{pmatrix}\right\}\). Which one of the following sets is an orthonormal basis of \(V\) with respect to \(\langle x,y\rangle_P\)?

Let \(T: \mathbb{R}^3 \to \mathbb{R}^3\) be the linear transformation which reflects every vector in \(\mathbb{R}^3\) through a two-dimensional subspace of \(\mathbb{R}^3\). Let \(P \in \mathbb{R}^{3 \times 3}\) be the matrix representation of \(T\) using the basis

\[ \left\{ \begin{pmatrix} 1 \\ 0 \\ 0 \end{pmatrix}, \begin{pmatrix} 0 \\ 1 \\ 0 \end{pmatrix}, \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \right\}. \]

Then the value of \(2 \times \text{trace}(P) - 3 \times \text{determinant}(P)\) is equal to ______. (answer in integer)

Let \(P\) be a \(3 \times 3\) real symmetric positive definite matrix. Which of the following statements is/are TRUE?

Let \( M_3(\mathbb{R}) \) be the vector space of all \( 3 \times 3 \) real matrices over \( \mathbb{R} \) under usual matrix addition and scalar multiplication. Let \( T_3(\mathbb{R}) \) be the set of all \( 3 \times 3 \) real upper triangular matrices. Which one of the following is TRUE?